A mixture composed of 94% ammonium nitrate and 6% fuel oil, by weight. Used as a blasting
agent.

Arcing

Malfunction of an electric blasting cap caused by excessive electrical amperage or current.

Back Break

Rock broken beyond the limits of the rear row of holes in a blast pattern.

Bench

The horizontal ledge in an excavation or mining operation along which holes are drilled vertically.

Binary Explosive

An explosive prepared by mixing 2 non-explosive materials which when combined form a cap-sensitive
explosive.

Blast

The action of breaking and displacing rock by means of explosives. SHOT also means blast.

Blasting Agent

A material or mixture consisting of a fuel and oxidizer used for blasting, but not classified as a high explosive, in
which none of the ingredients are classified as an explosive. The finished product is not cap-sensitive.

Blasting Cap
(See Detonators)

A metallic tube closed at one end, containing a charge of one or more detonating compounds, and designed to initiate
detonation.

Blast Hole

A hole drilled in rock or other material for the placement of explosives.

Blasting Machine

A battery-activated device designed for the purpose of energizing electric blasting caps.

Blockhole

A hole drilled in rock or other material for the placement of explosives.

Booster

An explosive chemical compound used for priming or intensifying an explosion.

Bridging

Where the continuity of a column of explosives in a borehole is broken, either by improper explosive placement, or
where some foreign matter has separated the charge in the hole.

Burden

The distance in feet from an explosive charge, in the direction of relief, to the nearest free or open
face.

Collar

The top of a borehole.

Capacitor-Discharge

A type of electric direct current blasting machine which uses batteries to activate a series of capacitors, whose
stored energy is released to energize a blasting circuit.

Connector

A device used as a delay in a non-electric circuit, connecting one hole in the circuit with another, or one row of
holes to other rows of holes.

Cushion Blasting & Explosives Inspector

The technique of firing a single row of holes along a neat excavation line to shear the web between the closely drilled
holes.

Cutoff

A portion of a blast which fails to detonate.

Deck

A portion of a borehole loaded with explosives that is separated from other charges in the same borehole by inert
material.

Delay Interval

The time in milliseconds between successively detonated charges.

Density

The weight or mass per unit volume of a material (i.e. grams/cc, lb./cu. ft.). The density of explosive materials may
be measured in terms of specific gravity.

Detonation

An explosive reaction that consists of the propagation of a shock wave through the explosive accompanied by a chemical
reaction that furnishes energy to sustain the shock propagation in a stable manner, with gaseous formation and pressure expansion following shortly thereafter.

Detonating Cord

A flexible cord containing a center core of a high explosive which, when detonated, will have sufficient strength to
detonate cap-sensitive explosives with which it is in contact.

Detonation Velocity

The rate at which the detonation wave travels through a column of explosives.

Any undesirable electric energy, (i.e., stray current, static electricity, lightning, current induced by radio
frequency energy or high voltage power lines).

Fragmentation

The extent to which rock is broken by blasting.

Free Face

The surface which is uncovered to provide room for expansion and movement when detonation occurs.

Fume Characteristic

Measure of the amount of toxic gases produced by detonation of an explosive. The U. S. Bureau of Mines fume classes are
based on the cubic feet of poisonous gases produced by a 1 ¼" x 8" cartridge.

Fumes

The toxic oxides of nitrogen produced by a detonation.

Fuse Lighters

Special devices for the purpose of igniting safety fuse.

Galvanometer

An electrical instrument designed expressly for the purpose of measuring resistance and monitoring continuity of an
electrical blasting circuit.

Ground Vibration

A wave transmitted through the ground that causes the surface particles of ground to oscillate as it
passes.

Hang Fire

The partial burning of a charge that may eventually result in an explosion.

Ignitacord

Thin wire-bound fuse with one foot markings. Its core burns with a very hot external flame at a rate of eight to twenty
seconds per foot.

Initiation

The act of starting the detonation of explosive material.

Lift Shot

A blast which is confined on all sides and has no free face to provide relief.

Loading Factor

Weight of explosive per foot in a borehole.

Mat

Used to cover a blast to hold down ejected debris usually made of woven wire cable or rope.

Millisecond

1/1000th of a second

Misfire

A charge, or part of a charge, which has failed to fire as planned. All misfires are to be considered extremely
dangerous until the cause of the misfire has been determined.

Magazine

Any building or structure, used for the storage of explosive materials.

Mud-Capping

(sometimes know as "bulldozing," "adobe blasting", or "dobying"). The breaking of bounders by placing a quantity of
explosives against a rock or boulder without confining the explosives in a drill hole.

Multiple Priming

Two or more cartridges containing initiating devices, placed in the same borehole.

Overburden

The material to be shot overlying the materials being mined, (e.g., shale overlying limestone, or sandstone overlying
coal).

Pattern

An arrangement of boreholes laid out in a blast area, expressed in terms of burden and spacing measured in
feet.

Permissible

Explosives approved by the U. S. Bureau of Mines for use in gassy underground mines. Determining factors are the
volume, temperature, and duration of flames produced during detonation.

Powder

A generic term describing any explosive.

Powder Column

A continuous length of explosives loaded into a borehole.

Powder Factor

The ratio of weight of explosive to tons or cubic yards of material blasted.

Pre-Blasting Survey

An inspection and documentation of the condition of a structure prior to blasting.

Pre-Splitting

Stress relief involving a single row of holes drilled along a neat excavation line, where detonation of explosives in
the holes causes shearing of the web or rock between the holes. Pre-split holes may be fired in advance of production holes.

Prill

Small porous pellet or bead of ammonium nitrate.

Primary Blasting

The blasting operation by which the original rock formation is dislodged from its natural locations.

Primer

A cartridge or container of high explosives into which a detonator is properly inserted or detonating cord if properly
attached.

Propagation

The detonation of a charge by shock or pressure from an adjacent explosion.

Quarry Cord

Burns with an external flame at a rate of one and one-half feet per second, and is used for firing multiple charges
simultaneously.

Round

A group or set of blast holes constituting a complete cut or shot.

Safety Fuse

A flexible cord containing an internal burning medium by which fire is conveyed at a continuous and uniform rate for
the purpose of firing a blasting cap.

Scaled Distance

The ratio calculated by dividing the actual distance in feet, from the blast site to the nearest structure, by the
square root of the maximum weight of an explosive charge per millisecond delay period.

Secondary Blasting

The reduction of over size material by the use of explosives to a size required for handling. May be accomplished by
mudcapping and blockholing.

Seismograph

An instrument that measures and may furnish a permanent record of earthborne vibrations and air overpressure induced by
blasting.

Sensitiveness

A measure of the propagating ability of explosives.

Sensitivity

A measure of the ease with which an explosive can be initiated. Various types of sensitivity are expressed as: cap
sensitivity, impact sensitivity, bullet sensitivity.

Sequential Blasting Machine

A machine for supplying electrical energy to separate series of circuits at precise time intervals. Use of the delays
between circuits within the machine enables an increase in the number of delay intervals available.

Shunt

A piece of metal connecting the stripped ends of electric cap legwires to prevent stray currents from causing
accidental detonation of the cap. The act of deliberately shorting any portion of an electrical blasting circuit.

Simplex Wire

Single electrical conductor enclosed in an insulating sleeve.

Slurry or Water Gel

Explosive materials containing substantial amounts of water and high proportions of ammonium nitrate, some of which is
in water solution. May be a high explosive or a blasting agent depending on sensitizing materials used. May be loaded in bulk or tube type cartridges.

Spacing

Distance in feet between boreholes in a row measured perpendicular to the burden and parallel to the free
face.

Specific Gravity

The ratio of the density of a material to the density of water, (e.g., specific gravity of free-flowing ANFO is
approximately equal to 0.85). Specific gravities less than 1.0 are lighter than water; specific gravities greater than 1.0 are heavier than water.

Spring

May be referred to as CHAMBERING. The creation of a pocket in the bottom of a drill hole by detonating an unconfined
quantity of explosives in order that larger quantities of explosives may be loaded after the hole has cooled.

Stemming

An inert material used to confine or separate explosives in a borehole.

Strength

The measure of the energy content of an explosive in relation to nitroglycerine dynamite.